This invention pertains to the art of fluid sensing devices and, more particularly, to a device for sensing the presence or absence of a liquid at a preselected level.
The invention is particularly applicable to a liquid level indicator system useful for motor vehicle applications such as monitoring engine oil level, engine coolant level, or other motor vehicle liquid levels. However, it will be appreciated to those skilled in the art that the invention could be readily adapted for use in other environments where there is a need for a stable liquid level sensing system subject to dynamic operating conditions in a harsh environment.
There has always been a need for improved liquid monitoring devices for particular applications with motor vehicle systems. The various forms and types of liquid level indicator systems that have heretofore been employed in the industry, have met with varying degrees of success. These prior indicator systems have ranged from electromechanical devices to complex systems of fiber optics. It has been found that the defects present in most such prior systems are such that the systems themselves are of limited economic and practical value.
Prior known electromechanical systems have been particularly sensitive to vehicle motion and vehicle level. The transient conditions resulting from vehicle motion have either generated false alarms or required complex indicator insulating structures. The fiber optic systems, apart from their excessive complexities, have also proved overly sensitive to liquid contamination, color changes, moisture, and the like which have limited their practical value.
The present invention contemplates a new and improved device which overcomes the above referred to problems and others to provide a new liquid level indicator assembly which is simple in design, economical to manufacture, readily adaptable to a plurality of uses with fluid systems having a variety of dimensional characteristics, applications, and environments and which provides improved liquid level indication.